Updates to package size check

Currently, if the package size grows larger than a threshold, the Trigger:package job on gitlab.com or the branch builds on dev.gitlab.org will fail. Blocking the MR until the size is reduced, or the limit is increased (which requires maintainer intervention).

Problems with current approach

• It doesn't take into account the large size difference between EE and CE packages, so only triggers on EE builds. Meaning we may miss large jumps in the CE package
• The size growth may be unrelated to the MR it is tied to. Blocking progress for a potentially unrelated issue
• Moving past the issue can be limited by maintainer availability
• We aren't storing any data related to this threshold being hit

Proposal:

• Instead of erroring when the alert is hit, use some of the incident management features to handle the issue. Allowing development to proceed.
• Consider different thresholds for EE and CE packages